Process for mass-dyeing of thermoplastics: polystyrene and styrene copolymers with indoline methine dyes

ABSTRACT

Process for mass-dyeing of thermoplastics, characterized in that the dyestuffs used are of the formula ##STR1## in which X designates a radical ##STR2## R designates hydrogen or alkyl, R 1  and R 2  designate alkyl, 
     R 3  designates hydrogen, cyano, aroyl, alkoxycarbonyl, alkylcarbonyl or carbamoyl, 
     R 4  designates aryl, 
     R 5  designates alkyl, alkylcarbonyl, alkoxycarbonyl or aryl, 
     R 6  designates alkyl, aryl, aralkyl or aralkenyl, and 
     Y designates O or NR 7 , with R 7  having the meaning hydrogen, alkyl, aralkyl or aryl, it being possible for the radicals which have been mentioned for R 7  and R 1  -R 7  and which contain C--H or N--H bonds to be substituted, and wherein the ring A can carry 1, 2 or 3 substituents from the series comprising halogen, cyano, alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, aralkoxycarbonyl, carbamoyl, sulphamoyl, alkylsulphonyl and arylsulphonyl, or can have a benzene ring fused to it, it being possible for the radicals which have been mentioned as substituents of the ring A and which contain C--H or N--H bonds to be substituted.

The invention relates to a process for mass-dyeing of thermoplastics,which is characterised in that the dyestuffs used are of the formula##STR3## in which

X designates a radical ##STR4##

R designates hydrogen or alkyl,

R₁ and R₂ designate alkyl,

R₃ designates hydrogen, cyano, aroyl, alkoxycarbonyl, alkylcarbonyl orcarbamoyl,

R₄ designates aryl,

R₅ designates alkyl, alkylcarbonyl, alkoxycarbonyl or aryl,

R₆ designates alkyl, aryl, aralkyl or aralkenyl, and

Y designates O or NR₇, with R₇ having the meaning hydrogen, alkyl,aralkyl or aryl, it being possible for the radicals which have beenmentioned for R₇ and R₁ -R₇ and which contain C--H or N--H bonds to besubstituted, and wherein the ring A can carry 1, 2 or 3 substituentsfrom the series comprising halogen, cyano, alkyl, alkoxy, alkylcarbonyl,alkoxycarbonyl, aralkoxycarbonyl, carbamoyl, sulphamoyl, alkylsulphonyland arylsulphonyl, or can have a benzene ring fused to it, it beingpossible for the radicals which have been mentioned as substituents ofthe ring A and which contain C--H or N--H bonds to be substituted.

Compounds which are preferably employed in the process according to theinvention are those of the formula ##STR5## in which

X' represents ##STR6## and

R' designates hydrogen, methyl or ethyl,

R₁ ' and R₂ ' designate methyl or ethyl,

R₃ ' designates hydrogen, cyano, aroyl, in particular benzoyl andnaphthoyl, alkoxycarbonyl, in particular (C₁ -C₄ -alkoxy)-carbonyl orcarbamoyl,

R₄ ' designates phenyl which can be substituted by methyl, ethyl,methoxy, ethoxy or chlorine,

R₅ ' designates methyl, methoxycarbonyl or ethoxycarbonyl, or phenylwich can be substituted by methyl and/or ethyl,

R₆ ' designates C₁ -C₄ -alkyl, phenyl, chlorophenyl or methylphenyl, orphenyl-C₁ -C₃ -alkyl which can be substituted in the phenyl nucleus bychlorine and/or methyl, or designates phenylallyl or phenoxyethyl,

Y' designates O or NR₇, wherein

R₇ ' represents alkyl, in particular C₁ -C₄ -alkyl, or aralkyl, inparticular phenyl-C₁ -C₃ -alkyl, L designates hydrogen, chlorine, cyano,methyl, ethyl, methoxy, ethoxy, methoxycarbonyl, ethoxycarbonyl orbenzyloxycarbonyl, or sulphamoyl or carbamoyl which is optionallysubstituted by methyl, ethyl or phenyl, or designates methylsulphonyl orphenylsulphonyl, and M and Q designate hydrogen, methyl, ethyl, methoxy,ethoxy, chlorine or methoxycarbonyl, and two of the substituents L, Mand Q together can form a fused benzene ring.

Of particular interest are dyestuffs of the formula II, in which

R' designates hydrogen or methyl,

R₁ ' and R₂ ' designate methyl,

R₃ ' designates hydrogen, cyano or benzoyl,

R₄ ' designates phenyl which can be substituted by methyl, methoxyand/or chlorine,

R₅ ' designates methyl or methoxycarbonyl,

L designates hydrogen, methoxycarbonyl, cyano, methoxy or chlorine,

M and Q designate hydrogen,

Y' designates O, and

R₆ ' designates C₁ -C₄ -alkyl, phenyl, chlorophenyl or methylphenyl, orphenyl-C₁ -C₃ -alkyl, the phenyl radical of which can be substituted bychlorine or methyl, or designates phenoxyethyl.

The compounds ##STR7## are very particularly preferably employed in theprocess according to the invention.

The methine dyestuffs to be used according to the invention representknown compounds. The dyestuffs of the general formula Ia areadvantageously prepared by condensation of pyrazolone-4-aldehydes oftheir N,N-dialkylsubstituted enamines with the appropriate2-methyleneindolines (see German Auslegeschrift No. 1,154,894), or byreaction of 2-methyleneindoline-ω-aldehydes with the appropriatepyrazolone (see German Auslegeschrift No. 1,172,487). The compounds ofthe formula Ib are obtained by condensation of the2-methyleneindoline-ω-aldehydes with the appropriate cyanoacetates (seeGerman Auslegeschrift No. 1,172,387 or 1,569,728).

Some particularly suitable compounds are listed in Tables 1 and 2 whichfollow.

                                      TABLE 1                                     __________________________________________________________________________     ##STR8##                                    IIa                                                                   Shade of the                             Compound                                                                            L     M Q R' R.sub.1 '                                                                        R.sub.2 '                                                                        R.sub.3 '                                                                        R.sub.4 '                                                                         R.sub.5 '                                                                          polystyrene dyeing                       __________________________________________________________________________    1     H     H H CH.sub.3                                                                         CH.sub.3                                                                         CH.sub.3                                                                         H  C.sub.6 H.sub.5                                                                   CH.sub.3                                                                           orange                                   2     5-CH.sub.3 O                                                                        H H CH.sub.3                                                                         CH.sub.3                                                                         CH.sub.3                                                                         H  C.sub.6 H.sub.5                                                                   CH.sub.3                                                                           orange                                   3     5-CH.sub.3 O.sub.2 C                                                                H H CH.sub.3                                                                         CH.sub.3                                                                         CH.sub.3                                                                         H  C.sub.6 H.sub.5                                                                   CH.sub.3                                                                           orange                                   4     5-Cl  H H CH.sub.3                                                                         CH.sub.3                                                                         CH.sub.3                                                                         H  C.sub.6 H.sub.5                                                                   CH.sub.3                                                                           orange                                   5     H     H H CH.sub.3                                                                         CH.sub.3                                                                         CH.sub.3                                                                         CN C.sub.6 H.sub.5                                                                   CH.sub.3                                                                           orange                                   6     5-CH.sub.3 O                                                                        H H CH.sub.3                                                                         CH.sub.3                                                                         CH.sub.3                                                                         CN C.sub.6 H.sub.5                                                                   CH.sub.3                                                                           orange                                   7     5-CH.sub.3 O.sub.2 C                                                                H H CH.sub.3                                                                         CH.sub.3                                                                         CH.sub.3                                                                         CN C.sub.6 H.sub.5                                                                   CH.sub.3                                                                           orange                                   8     5-Cl  H H CH.sub.3                                                                         CH.sub.3                                                                         CH.sub.3                                                                         CN C.sub.6 H.sub.5                                                                   CH.sub.3                                                                           orange                                   9     H     H H CH.sub.3                                                                         CH.sub.3                                                                         CH.sub.3                                                                         H  C.sub.6 H.sub.5                                                                   CO.sub.2 CH.sub.3                                                                  yellowish red                            10    5-CH.sub.3 O                                                                        H H CH.sub.3                                                                         CH.sub.3                                                                         CH.sub.3                                                                         H  C.sub.6 H.sub.5                                                                   CO.sub.2 CH.sub.3                                                                  yellowish red                            11    5-CH.sub.3 O.sub.2 C                                                                H H CH.sub.3                                                                         CH.sub.3                                                                         CH.sub.3                                                                         H  C.sub.6 H.sub.5                                                                   CO.sub.2 CH.sub.3                                                                  yellowish red                            12    5-Cl  H H CH.sub.3                                                                         CH.sub.3                                                                         CH.sub.3                                                                         H  C.sub.6 H.sub.5                                                                   CO.sub. 2 CH.sub.3                                                                 yellowish red                            13    H     H H CH.sub.3                                                                         CH.sub.3                                                                         CH.sub.3                                                                         H  p-tolyl                                                                           CH.sub.3                                                                           orange                                   14    5-CH.sub.3 O                                                                        H H CH.sub.3                                                                         CH.sub.3                                                                         CH.sub.3                                                                         H  p-tolyl                                                                           CH.sub.3                                                                           orange                                   15    5-CH.sub.3 O.sub.2 C                                                                H H CH.sub.3                                                                         CH.sub.3                                                                         CH.sub.3                                                                         H  p-tolyl                                                                           CH.sub.3                                                                           orange                                   16    5-Cl  H H CH.sub.3                                                                         CH.sub.3                                                                         CH.sub.3                                                                         H  p-tolyl                                                                           CH.sub.3                                                                           orange                                   __________________________________________________________________________

The dyestuffs listed in Table 2 below dye polystyrene yellow when usedin customary mass-dyeing processes.

                                      TABLE 2                                     __________________________________________________________________________     ##STR9##                                                                     Compound                                                                            L     M  Q R'  R.sub.1 '                                                                        R.sub.2 '                                                                         R.sub.3 '                                                                        R.sub.6 '                                      __________________________________________________________________________    17    H     H  H CH.sub.3                                                                          CH.sub.3                                                                         CH.sub.3                                                                          H  C.sub.2 H.sub.5                                18    5-CH.sub.3 O                                                                        H  H CH.sub.3                                                                          CH.sub.3                                                                         CH.sub.3                                                                          H  C.sub.2 H.sub.5                                19    5-CH.sub.3 O.sub.2 C                                                                H  H CH.sub.3                                                                          CH.sub.3                                                                         CH.sub.3                                                                          H  C.sub.2 H.sub.5                                20    5-Cl  H  H CH.sub.3                                                                          CH.sub.3                                                                         CH.sub.3                                                                          H  C.sub.2 H.sub.5                                21    H     H  H CH.sub.3                                                                          CH.sub.3                                                                         CH.sub.3                                                                          H  CH.sub.2C.sub.6 H.sub.5                        22    5-CH.sub.3 O                                                                        H  H CH.sub.3                                                                          CH.sub.3                                                                         CH.sub.3                                                                          H  CH.sub.2C.sub.6 H.sub.5                        23    5-CH.sub.3 O.sub.2 C                                                                H  H CH.sub.3                                                                          CH.sub.3                                                                         CH.sub.3                                                                          H  CH.sub.2C.sub.6 H.sub.5                        24    5-Cl  H  H CH.sub.3                                                                          CH.sub.3                                                                         CH.sub.3                                                                          H  CH.sub.2C.sub.6 H.sub.5                        25    H     H  H CH.sub.3                                                                          CH.sub.3                                                                         CH.sub.3                                                                          CN CH.sub.2C.sub.6 H.sub.5                        26    5-CH.sub.3 O                                                                        H  H CH.sub.3                                                                          CH.sub.3                                                                         CH.sub.3                                                                          CN CH.sub.2C.sub.6 H.sub.5                        27    5-CH.sub.3 O.sub.2 C                                                                H  H CH.sub.3                                                                          CH.sub.3                                                                         CH.sub.3                                                                          CN CH.sub.2C.sub.6 H.sub.5                        28    5-Cl  H  H CH.sub.3                                                                          CH.sub.3                                                                         CH.sub.3                                                                          CN CH.sub.2C.sub.6 H.sub.5                        29    H     H  H CH.sub.3                                                                          CH.sub.3                                                                         CH.sub.3                                                                          H  4-chlorobenzyl                                 30    5-CH.sub.3 O                                                                        H  H CH.sub.3                                                                          CH.sub.3                                                                         CH.sub.3                                                                          H  "                                              31    5-CH.sub.3 O.sub.2 C                                                                H  H CH.sub.3                                                                          CH.sub.3                                                                         CH.sub.3                                                                          H  "                                              32    5-Cl  H  H CH.sub.3                                                                          CH.sub.3                                                                         CH.sub.3                                                                          H  "                                              33    H     H  H CH.sub.3                                                                          CH.sub.3                                                                         CH.sub.3                                                                          H  2-chlorobenzyl                                 34    5-CH.sub.3 O                                                                        H  H CH.sub. 3                                                                         CH.sub.3                                                                         CH.sub.3                                                                          H  "                                              35    5-CH.sub.3 O.sub.2 C                                                                H  H CH.sub.3                                                                          CH.sub.3                                                                         CH.sub.3                                                                          H  "                                              36    5-Cl  H  H CH.sub.3                                                                          CH.sub.3                                                                         CH.sub.3                                                                          H  "                                              __________________________________________________________________________

In the process according to the invention, it is also possible to employmixtures of various dyestuffs of the formula I and/or mixtures ofdyestuffs of the formula I with other dyestuffs and/or inorganic ororganic pigments.

The following may be mentioned as examples of suitable thermoplastics:cellulose esters, such as cellulose nitrate, cellulose acetate,cellulose triacetate, cellulose acetobutyrate and cellulose propionate,cellulose ethers, such as methylcellulose, ethylcellulose, andbenzylcellulose, polyethylene terephthalate, linear saturated polyesterresin plastics, polyamides, aniline resin plastics, polycarbonates,polyethylene, polypropylene, polystyrene, polyvinylcarbazole,polyvinylchloride, in particular rigid PVC, polyisobutylene,polymethacrylates, polyvinylidenechloride, polytetrafluoroethylene,polytrifluoroethylene, polyacrylonitrile, polyoxomethylenes, linearpolyurethanes, polyphenylene oxide, polysulphones and copolymers, suchas vinyl chloride/vinyl acetate copolymers and in particular styrenecopolymers, such as acrylonitrile/butadiene/styrene copolymers (ABS),styrene/acrylonitrile copolymers (SAN), styrene/butadiene copolymers(SB) and styrene/α-methylstyrene copolymers (SMS).

The new process is particularly suitable for mass-dyeing polystyrene andstyrene copolymers, in particular ABS.

The dyeings obtained are distinguished by good light fastnesses andweathering fastnesses. Surprisingly, the dyestuffs according to theinvention possess, in the thermoplastics, extremely high thermalstabilities and stabilities to sublimation.

In U.S. Pat. No. 2,840,443, methine dyestuffs, for example of theformula ##STR10## are proposed for dyeing synthetic, polymeric,thermoplastic materials. In comparison to these dyestuffs, the dyestuffsto be used according to the invention are distinguished by substantiallyhigher thermal stabilities. This is of critical importance in theindustrial processing. This advantage could not be foreseen on the basisof the prior art, and is accordingly to be regarded as surprising.

EXAMPLE 1

0.1 part by weight of the dyestuff of the formula ##STR11## 2 parts byweight of titanium dioxide (Bayertitan R-FK-D) and 100 parts by weightof polystyrene granules are mixed on a roller stand for 2 hours, in aclosed vessel. The mixture obtained is extruded at approx. 230° C. togive extrudates of 2 cm width, and these are again granulated. Thegranules are injection moulded at 230°-240° C. with the aid of aninjection moulding machine to give mouldings. Mouldings which are dyedorange and have a high stability to light are obtained.

EXAMPLE 2

0.05 part by weight of the dyestuff of the formula (III) and 100 partsby weight of polystyrene granules are mixed on a roller stand for 2hours, in a closed vessel. The mixture is then injection moulded at230°-240° C. with the aid of an injection moulding machine to givemouldings. The transparent mouldings which are dyed orange-red have highlight fastness.

EXAMPLE 3

If the dyestuff of the formula (III) is replaced by the dyestuff of theformula ##STR12## and the procedure described in Example 1 is otherwisefollowed, mouldings which are dyed greenish-yellow and have high lightfastness are obtained.

EXAMPLE 4

If 0.05 part by weight of the dyestuff of the formula (IV) and 100 partsby weight of polystyrene granules are mixed, and the procedure describedin Example 2 is otherwise followed, mouldings which are dyedgreenish-yellow and have high light fastness are obtained.

EXAMPLE 5

If the polystyrene granules are replaced by ABS granules and theprocedure described in Example 1 is otherwise followed, mouldings whichare dyed orange and have high light fastness are obtained. The dyestuffof the formula (III) can be employed in ABS even at temperatures above280° C. without noticeable changes in shade occurring or it beingpossible to detect sublimation.

EXAMPLE 6

If 0.1 part by weight of the dyestuff of the formula (IV), 2 parts byweight of titanium dioxide (Bayertitan R-FK-D) and 100 parts by weightof ABS granules are mixed, and the procedure described in Example 1 isotherwise followed, mouldings which are dyed greenish-yellow and havehigh light fastness are obtained.

The dyestuff of the formula (IV) can be employed in ABS even attemperatures above 280° C. without noticeable changes in shade occurringor it being possible to detect sublimation.

EXAMPLE 7

If the dyestuff of the formula (III) is replaced by a compound of theformula ##STR13## and the procedures described in Examples 1 and 2 areotherwise followed, opaque or transparent mouldings which are dyedorange and have high light fastness are obtained.

EXAMPLE 8

If, instead of the dyestuff of the formula (III), the dyestuff of theformula ##STR14## is used and the procedures described in Examples 1 and2 are otherwise followed, opaque or transparent mouldings which are dyedgreenish-yellow and have high light fastness are obtained.

I claim:
 1. Process for mass-dyeing of polystyrene and styrenecopolymers, characterised in that the dyestuffs used are of the formula##STR15## in which X designates a radical ##STR16## R designateshydrogen or alkyl, R₁ and R₂ designate alkyl,R₃ designates hydrogen,cyano, aroyl, alkoxycarbonyl, alkylcarbonyl or carbamoyl, R₄ designatesaryl, R₅ designates alkyl, alkylcarbonyl, alkoxycarbonyl or aryl, R₆designates alkyl, aryl, aralkyl or aralkenyl, and Y designates O or NR₇,with R₇ having the meaning hydrogen, alkyl, aralkyl or aryl, it beingpossible for the radicals which have been mentioned for R₇ and R₁ -R₇and which contain C--H or N--H bonds to be substituted, and wherein thering A can carry 1, 2 or 3 substituents from the series comprisinghalogen, cyano, alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl,aralkoxycarbonyl, carbamoyl, sulphamoyl, alkylsulphonyl andarylsulphonyl, or can have a benzene ring fused to it, it being possiblefor the radicals which have been mentioned as substituents of the ring Aand which contain C--H or N--H bonds to be substituted.
 2. Processaccording to claim 1, characterised in that compounds of the formula##STR17## are used, in which X' represents ##STR18## and R' designateshydrogen, methyl or ethyl,R₁ ' and R₂ ' designate methyl or ethyl, R₃ 'designates hydrogen, cyano, aroyl, in particular benzoyl and naphthoyl,alkoxycarbonyl, in particular (C₁ -C₄ -alkoxy)-carbonyl or carbamoyl, R₄' designates phenyl which can be substituted by methyl, ethyl, methoxy,ethoxy or chlorine, R₅ ' designates methyl, methoxycarbonyl orethoxycarbonyl, or phenyl which can be substituted by methyl and/orethyl, R₆ ' designates C₁ -C₄ -alkyl, phenyl, chlorophenyl ormethylphenyl, or phenyl-C₁ -C₃ -alkyl which can be substituted in thephenyl nucleus by chlorine and/or methyl, or designates phenylallyl orphenoxyethyl, Y' designates O or NR₇ ', wherein R₇ ' represents alkyl,in particular C₁ -C₄ -alkyl, or aralkyl, in particular phenyl-C₁ -C₃-alkyl, L designates hydrogen, chlorine, cyano, methyl, ethyl, methoxy,ethoxy, methoxycarbonyl, ethoxycarbonyl or benzyloxycarbonyl, orsulphamoyl or carbamoyl which is optionally substituted by methyl, ethylor phenyl, or designates methylsulphonyl or phenylsulphonyl, and M and Qdesignate hydrogen, methyl, ethyl, methoxy, ethoxy, chlorine ormethoxycarbonyl, and two of the substituents L, M and Q together canform a fused benzene ring.
 3. Process according to claim 1,characterised in that compounds of the formula II are used, in whichR'designates hydrogen or methyl, R₁ ' and R₂ ' designate methyl, R₃ 'designates hydrogen, cyano or benzoyl, R₄ ' designates phenyl which canbe substituted by methyl, methoxy and/or chlorine, R₅ ' designatesmethyl or methoxycarbonyl, L designates hydrogen, methoxycarbonyl,cyano, methoxy or chlorine, M and Q designate hydrogen, Y' designates O,and R₆ ' designates C₁ -C₄ -alkyl, phenyl, chlorophenyl or methylphenyl,or phenyl-C₁ -C₃ -alkyl, the phenyl radical of which can be substitutedby chlorine or methyl, or designates phenoxyethyl.
 4. Process accordingto claim 1, characterised in that the dyestuff of the formula ##STR19##is used.
 5. Process according to claim 1, characterised in that thedyestuff of the formula ##STR20## is used.
 6. Process according to claim1, for dyeing polystyrene.
 7. Process according to claim 1, for dyeingpolystyrene copolymers.
 8. Process according to claim 1, for dyeing ABS.